Cold or heat treatments in temperable treatment chambers are generally known as therapeutic procedures in physical therapy. They are felt to be an effective approach for numerous kinds of indications. Such treatments range from the purely medical-therapeutic realm, e.g. cold applications for rheumatic diseases, all the way to the realm of prophylaxis and physical fitness, e.g. heat application in saunas. Consequently, the term "patient" is used below according to the invention to also refer to healthy persons who merely use such installations for reasons of prophylaxis or physical fitness. Moreover, it is also known that there is an increased oxygen demand as an immediate or subsequent reaction to a cold or heat treatment. Furthermore, it is also known that, with certain indications, an elevated oxygen supply likewise has a therapeutic as well as an overall performance-enhancing effect. Such an improved oxygen supply could be achieved by enriching the atmosphere in the treatment chamber with oxygen. However, for safety reasons, this poses problems and would require complex technical safety measures.